OnKeyUp equivalent for ASP.NET AJAX

Question

I'm fairly new to using AJAX in ASP.NET (although I am very familiar with low level Javascript AJAX) so extra detail would be much appreciated. I'd like to do an onkeyup event on a textbox and call a method in my code behind. I've read some stuff about using Page Methods with the Script Manager tag but I couldn't get the syntax quite right to make it work. Basically here's what I'm trying to do

myfile.aspx

<asp:TextBox ID="textbox1" runat="server" onkeyup="MyMethod()" />
<asp:Label ID="label1" runat="server" />

myfile.aspx.cs

protected MyMethod()
{
    String val = textbox1.Text;
    String result = // do some LINQ to SQL stuff and get a some data
    label1.Text = result;
}

Answer 1

For those interested, I found this to be the most helpful.

http://forums.asp.net/t/1202543.aspx